A few words about the tool

The tableau can be read as follows. The example you get when
reloading the page corresponds to the LP with constraints
x2 + x0 = 1, x3 + x1 = 1, x4 + x0 + x1 = 1.5, non-negativity
constraints for all xi, and the objective
is to maximize x0 + 2x1. The objective can be read as the other lines
as obj - x0 - 2x1 = 0.
To give an optical hint of how to read
the tableau, the vertical bold line can be seen as the place where
we have the equality sign in the tableau.
Analogously, the horizontal bold line indicates the place
of the equality sign when reading the tableau as a dual-tableau.

A pivot on a given element can be performed by clicking on the
corresponding cell or pressing enter when the cell is selected.
A variable (basic or non-basic) can be deleted by right-clicking on it.
Numbers in the tableau as well as names of variables can be changed by
selecting the corresponding cell and starting to type.